Movable optical switching medium

ABSTRACT

Systems, devices, and methods may use input/output (I/O) apparatus and an optical switching medium to switch, or route, optical data signals. The optical switching medium may include a plurality of optical switching regions. The I/O apparatus may transmit optical data signals to and receive optical data signals from the optical switching medium to provide switching functionality.

The disclosure herein relates to systems, devices, and apparatus toprovide optical switching using a moveable optical switching medium.

SUMMARY

Illustrative systems, devices, and apparatus described herein mayinclude and use an optical switching medium. The optical switchingmedium may include a plurality of optical waveguides, and the pluralityof optical waveguides may define a plurality of optical switchingregions. Each of the optical switching regions may be described as beingcomprised of multiple discrete optical pathways where a plurality ofinputs are optically coupled to a plurality of optical outputs. Theplurality of inputs may be optically coupled to the plurality of outputsvia a plurality of optical pathways, or routes, that are configured toreceive one or more optical signals via optical inputs, and to directthe one or more optical signals to one or more optical outputs (e.g.,receive data from a source device and forward data to a destinationdevice). In one embodiment, each of the optical switching regions may bedifferent from each other such that each optical switching regionprovides a different switching functionality in that at least oneinput-to-output connection is different from another optical switchingregion. The plurality of optical switching regions within the opticalswitching medium may be thought of as a plurality of different fixedoptical pathways, and each of the optical switching regions may providedifferent routing than the other optical switching regions. The opticalswitching medium, which may be referred to more simply as a “switch”herein, may be movable with respect to the device or apparatus providingoptical signals to the optical switching medium and/or receiving opticalsignals from the optical switching medium.

One illustrative device may include an input/output (I/O) apparatus andan optical switching medium. The I/O apparatus may include a pluralityof optical transmitting portions and a plurality of optical receivingportions. The optical switching medium may include a plurality ofoptical waveguides defining a plurality of optical switching regions.The optical switching medium may be movable with respect to the I/Oapparatus to provide switching of optical signals between the pluralityof optical transmitting portions and the plurality of optical receivingportions by aligning the optical transmitting portions and opticalreceiving portions of the I/O apparatus with the plurality of opticalswitching regions to receive optical signals from the opticaltransmitting portions and to transmit optical signals to the opticalreceiving portions.

One illustrative apparatus may include an optical switching medium andan optical switching medium actuator. The optical switching medium mayinclude a plurality of optical waveguides defining a plurality ofoptical switching regions, and each of the plurality of waveguides mayextend from an optical input to an optical output, each opticalswitching region routing at least one optical input to a differentoptical output than at least one other optical switching region. Theoptical switching medium actuator may be operably coupled to the opticalswitching medium to move the optical switching medium to receive opticalsignals with the optical inputs of the optical waveguides of the opticalswitching regions and to transmit optical signals with the opticaloutput of the optical waveguides of the optical switching regions toprovide switching of the received optical signals. In other words, theoptical switching medium actuator may be described as moving the opticalswitching medium to present different optical switching regions to,e.g., the I/O apparatus such that the I/O apparatus can use the opticalswitching medium to provide switching of optical signals.

One illustrative system may include a plurality of optical switchingdevices, and each of the plurality of optical switching devices maycorrespond to and may be operable to switch optical signals to and froma node to other optical switching devices of the plurality of opticalswitching devices. Further, each optical switching device may include anoptical switching medium movable to switch optical signals to and fromthe node, and the optical switching medium may include a plurality ofoptical waveguides defining a plurality of optical switching regions.

The above summary is not intended to describe each embodiment or everyimplementation of the present disclosure. A more complete understandingwill become apparent and appreciated by referring to the followingdetailed description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram of an illustrative device including an opticalswitching medium.

FIG. 1B is a diagram of another illustrative device including an opticalswitching medium.

FIG. 2 is a plan view of an intersection of illustrative opticalpathways of the optical switching medium of FIGS. 1A-1B.

FIG. 3 is an image of an intersection of illustrative pathways of theoptical switching medium of FIGS. 1A-1B.

FIG. 4 is a diagram of an illustrative I/O apparatus for use with thedevice of FIG. 1A.

FIG. 5 is a cross-sectional view of the I/O apparatus and the opticalswitching medium of FIG. 4 taken across line 5-5′.

FIG. 6 is another cross-sectional view of the I/O apparatus and theoptical switching medium of FIG. 4 taken across line 6-6′.

FIG. 7 is another diagram of evanescent coupling between an illustrativewaveguide and an illustrative optical switching medium.

FIGS. 8A-8B are plan views of optical switching regions of anillustrative optical switching medium.

FIG. 9 is a diagram of a plurality of different optical switchingregions of an illustrative optical switching medium.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of illustrative embodiments,reference is made to the accompanying figures of the drawing which forma part hereof, and in which are shown, by way of illustration, specificembodiments which may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from (e.g., still falling within) the scope of the disclosurepresented hereby.

Illustrative systems, apparatus, and devices shall be described withreference to FIGS. 1-9. It will be apparent to one skilled in the artthat elements or processes from one embodiment may be used incombination with elements or processes of the other embodiments, andthat the possible embodiments of such methods, devices, and systemsusing combinations of features set forth herein is not limited to thespecific embodiments shown in the figures and/or described herein.Further, it will be recognized that the embodiments described herein mayinclude many elements that are not necessarily shown to scale. Stillfurther, it will be recognized that timing of the processes and the sizeand shape of various elements herein may be modified but still fallwithin the scope of the present disclosure, although certain timings,one or more shapes and/or sizes, or types of elements, may beadvantageous over others.

It has been noted that global internet traffic is expected to reach morethan 2.2 zettabytes per year by 2020. Such traffic growth drives theneed for mega-data centers, each with 100,000s of servers as, forexample, 75% of internet traffic remains within data centers (e.g.,“east-west” traffic). For example, some mega-data centers may haveinternal traffic orders of a magnitude larger than in/out traffic (e.g.,“north-south” traffic). Due to the need for high data bandwidth, dataflows through optical fibers in both east-west and north-southdirections. It is, at least, cost prohibitive to optically connect allpossible data sources and destinations with dedicated lines. Instead,optical switches are used to direct the internet traffic via theappropriate “avenues” as needed. As internet data traffic has increased,the need for efficient, high bandwidth optical switches has alsoincreased.

Further, advances in machine learning lead to computation withextremely-large data sets that cannot be completed on a single serverhave driven the need for more efficient interconnects within datacenter.Currently, the data in the interconnects may travel through anoptical-electrical-optical conversion due to scheduling datatransmissions and congestion control (such that, e.g., data can bestored in an electrical state such as memory since this is not possiblewith optical signals). Such electrical-optical conversion introducesenergy inefficiency into the system as well as requiring more systemhardware and complexity.

Data transmission may be maintained in the optical-to-optical domain inorder to improve high bandwidth density communication and improveresource utilization while enabling power efficient transfer. Forexample, some free space optical switches may utilize MEMs devicesmounted with mirrors to steer the optical signal (e.g., light, beams,rays, etc.) according to a desired input/output pathway. Further, forexample, liquid crystal on silicon (LCOS) may be used to beam steer byaltering the angle of reflection of a liquid crystal surface in the pathof the optical signal in response to an electrical signal. Such presentexamples may support connectivity of hundreds of ports but may requirecomplex installation and calibration and provide inadequate switchingspeed (tens of milliseconds) that make these approaches less thanoptimal for future datacenters.

Silicon or III-V-based guided-wave switches may be able to achievenanosecond to microsecond switching speeds but the losses and crosstalkmay limit these solutions to a small number of input-output couplings(e.g., less than tens of connections). Further, silicon-based solutionsmay use a cross-point matrix of connections that will scale in size andcomplexity according to the input-output count. Therefore, in brief,such silicon or III-V-based guided-wave switches may present challengesfor commercial development due to signal loss and poor yield.

In one or more embodiments, the illustrative systems, apparatus,devices, and methods may be described as modified head-disc interface asa non-deterministic optical switch for use in datacenters.

The illustrative systems, apparatus, devices, and methods may bedescribed as leveraging the mechanical architecture of a hard disc drive(HDD), including a spinning disc, a slider head flying (e.g., throughthe use of an air-bearing surface) over the disc, and a head-gimbalassembly (HGA) to suspend the head over the disc. It may be describedthat the illustrative systems, apparatus, devices, and methods provide a“head-disc optical switch (HDOS).” A multiplicity of optical signals(e.g., light) may be guided from input ports through a flexiblewaveguide channel attached to the suspension-gimbal into the inputcouplers at the back of the slider. The optical signals may bewaveguided through the head to the air-bearing surface, where thesignals are evanescently coupled into discrete-track-like patternedmedia on a spinning disc. The spinning disc acts as the optical “switch”in that different interconnection patterns in each sector of the discprovide a multiplicity of input-to-output connection combinations. Asthe head flies over the spinning disc, the optical signals areeffectively switched between different input-to-output connections, andthe optical signals are returned back in the same manner (e.g.,evanescent coupling back to the head and waveguided along thesuspension-gimbal) to the optical output ports.

Further, it may be described that the illustrative systems, apparatus,devices, and methods may provide non-deterministic switching. Forexample, the illustrative systems, apparatus, devices, and methods maybe agnostic to traffic demand. More specifically, the illustrativesystems, apparatus, devices, and methods do not change the opticalpathway according to increased demand through the action of the disc(although, e.g., it may be altered by control of the HGA and selectionof pre-defined optical pathways on the media). The switching is notdeterministic at each radius. The illustrative systems, apparatus,devices, and methods may be described as aiming at maximizing networkthroughput and may be ideally suited for uniform traffic across allinputs and outputs. It has been described that a non-deterministicoptical switch may only lose link bandwidth by a factor of two, giventhat the signal is allowed one intermediate step into the electricaldomain, which may be acceptable in an optically switched network tosupport arbitrary traffic patterns.

The illustrative systems, apparatus, devices, and methods may bedescribed as being significantly less complex and more spatially compactthan other non-deterministic switching technologies because, forexample, the illustrative systems, apparatus, devices, and methods donot require lenses, mirrors, prisms, collimators, other beam alignmentand collaboration structures or devices, etc.

Further, the illustrative systems, apparatus, devices, and methods maybe described as using I/O transceivers, or “heads,” flying over apatterned disc to create, or provide, dynamically changing opticalpathways that achieve optical switching as will be described furtherhere.

An illustrative device 10 including an optical switching medium 100 isdepicted in FIG. 1A. In this embodiment, the device 10 includes ahousing 12 and the optical switching medium 100 is positioned within thehousing 12. The housing 12 may include a pair of input/output (I/O)ports 14. The I/O ports 14 may be configured to received data signals,e.g., in the form of optical signals over fiber optics or any othermedium, that are to be switched.

The illustrative device 10 may also include an I/O apparatus 50 thatinteracts with the optical switching medium 100 to provide the switchingfunctionality provided herein. The I/O apparatus 50 may include aplurality of optical transmitting portions to transmit optical datasignals to the optical switching medium 100 and a plurality of opticalreceiving portions to receive optical data signals from the opticalswitching medium 100. The optical data signals received by the pluralityof optical receiving portions of the I/O apparatus 50 may be “switched”by the optical switching medium 100 and then transmitted back to the I/Oapparatus 50. In other words, the optical switching medium 100 presentsoptical switching regions comprised of different combinations of inputto output optical pathways as the medium 100 moves with respect to theI/O apparatus 50.

For example, if the I/O apparatus 50 includes four optical transmittingportions labeled A, B, C, D and four optical receiving portions labeledW, X, Y, Z, each of the optical data signals transmitted by opticaltransmitting portions A, B, C, D may be switched by the opticalswitching medium 100 to one of the four optical receiving portionslabeled W, X, Y, Z. In one illustrative instance, the optical datasignal transmitted from optical transmitting portion A may betransmitted, or “switched,” by the optical switching medium 100 tooptical receiving portion X, the optical data signal transmitted fromoptical transmitting portion B may be transmitted, or “switched,” by theoptical switching medium 100 to optical receiving portion Z, the opticaldata signal transmitted from optical transmitting portion C may betransmitted, or “switched,” by the optical switching medium 100 tooptical receiving portion Y, and the optical data signal transmittedfrom optical transmitting portion D may be transmitted, or “switched,”by the optical switching medium 100 to optical receiving portion W. Inanother illustrative instance, the optical data signal transmitted fromoptical transmitting portion A may be transmitted, or “switched,” by theoptical switching medium 100 to optical receiving portion X, the opticaldata signal transmitted from optical transmitting portion B may betransmitted, or “switched,” by the optical switching medium 100 tooptical receiving portion Y, the optical data signal transmitted fromoptical transmitting portion C may be transmitted, or “switched,” by theoptical switching medium 100 to optical receiving portion W, and theoptical data signal transmitted from optical transmitting portion D maybe transmitted, or “switched,” by the optical switching medium 100 tooptical receiving portion Z.

The I/O apparatus 50 may further include an actuator 52, a gimbalassembly 54, and a head portion 56 coupled to an end region of thegimbal assembly 54. The actuator 52 may be coupled to the housing 12 andthe gimbal assembly 54 and may be configured to move, or actuate, thegimbal assembly 54 and the head portion 56. More specifically, theactuator 52 may be configured to move, or actuate, the gimbal assembly54 and the head portion 56 relative to the optical switching medium 100,e.g., so as to align the plurality of optical transmitting and receivingportions with various regions of the optical switching medium 100 toprovide the switching functionality described herein.

In this example, the actuator 52 may provide arcuate, or partialrotational, motion of the gimbal assembly 54 and the head portion 56 soas to position the head portion 56 proximate (e.g., over, spaced apartfrom, etc.) multiple regions of the optical switching medium 100assuming that the optical switching medium 100 will be rotating, or inrotational motion, as described further herein. More specifically, theactuator 52 may provide arcuate, or partial rotational, motion of thegimbal assembly 52 and the head portion 56 about axis 51 (that extendsout of the page along the Z-axis).

The head portion 56 may include the plurality of optical transmittingand receiving portions as will be further described herein withreference to FIGS. 4-7 and may be optically coupled to the I/O ports 14via one or more or a plurality of optical channels 53 (depicted as twodashed lines in FIG. 1A) extending between the I/O ports 14 and the headportion 56. In one example, the optical channels 53 may be a pluralityof fibre optics. In another example, the optical channels 53 may be aplurality of optical waveguides in, or as a part of, a substrate. In oneor more embodiments, the suspension of the I/O apparatus 50 can bepopulated with (potentially) multiple head-gimbal-type assemblies andmultiple optical traces may be used for input and optical interconnects.

In one or more embodiments, it may be described that the I/O apparatus50 is “dumb” in that it does not include any logic or processing circuitconfigured to determine how or when any of the optical data signals areto be transmitted along the optical channels and to and from the opticalswitching medium 100. Instead, for example, the I/O apparatus 50 may bedescribed as simply being able to accurately and predictably provide aplurality of different switching configurations over time such that oneor more devices connected thereto “know” when and how to transmitoptical data signals thereto to achieve the switching, or routing, ofits optical data signals the one or more devices desire.

In other words, the head portion, or I/O transceiver, 56 may include noptical receivers, or optical inputs, to receive optical signals fromand n transmitters, or optical outputs, to transmit optical signals tothe optical switching medium, or “disc,” 100 via evanescent coupling.For example, the number of receivers and transmitters that can be placedin the alumina portion of the head portion 56 (e.g., an area of 50micrometers×0.77 micrometers) may provide over one thousand receiversand transmitters per head portion 56.

The optical switching medium 100 includes a plurality of opticalpathways 102 as shown in the enlarged view 101 of the optical switchingmedium 100 in FIG. 1A. The optical switching medium 100 may furtherinclude a substrate 104, within which and/or on which the plurality ofoptical pathways 102 may be located (e.g., formed, defined, etc.). Thesubstrate 104 may include (e.g., be formed of) one or more materialssuch as, for example, silicon, alumina, etc. In one embodiment, thesubstrate 104 may include silicon on insulator wafer. The substrate 104may define a planar, disc-like structure defining a top surface, abottom surface opposite the top surface, and an edge extending betweenthe top surface and the bottom surface. The thickness of the substrate104 may be substantially smaller than the other dimensions(perpendicular to the direction of the thickness) of the substrate 104.

It is to be understood that the substrate 104 and the optical pathways102 may be described as substrate that is moveable or rotatable so as topresent the optical pathways 102 to provide switching functionality asdescribed herein. Further, the substrate 104 and the optical pathways102 may be described as an array of optical waveguides, or waveguidearray, on or within a portion or piece of material (e.g., a block orsquare of material, a disc of material, etc.). Still further, thesubstrate 104 and the optical pathways 102 may be described as a movablearrangement of optical waveguides to provide switching functionality asdescribed herein.

The optical pathways 102 may include one or more polymers such as, e.g.,polyacrylate, polysiloxane, polynorbonene, silicon, silicon nitride,etc. and/or one or more glasses such as, e.g., chalcogenide glasses,toughed alkali-aluminosilicate sheet glass, etc. As shown in thisembodiment, the plurality of optical pathways 102 may be grouped intotwo groups: a first set, or group, of optical pathways 110 that areextending radially away from a center 103 of the optical switchingmedium 100 and a second set, or group, of optical pathways 112 that areextending circumferentially and/or accurately around the center 103 ofthe optical switching medium 100.

In other embodiments, the optical pathways 102 may form, or define,other patterns than shown in FIG. 1. For example, the optical pathways102 may lie in a grid with a first set, or group, of optical pathwaysthat are extending parallel to a first axis and a second set, or group,of optical pathways that are extending parallel to a second axisdifferent from the first axis (e.g., the second axis may beperpendicular to the first axis).

In other words, the optical switching medium, or disc, may be patterneduniquely in x sectors of the disc. These patterns are waveguides,creating unique optical pathways, or mappings, between n inputs and noutputs. In one example, the number of optical switches provided persquare inch of media may be able to provide 1 million switches per mediasurface.

Further, the optical switching medium, or disc, in the illustrativesystems, apparatus, devices, and methods may be described as includingservo sectors to help the head identify its location with respect to thesector mappings and waveguides. These servo tracks can be one both ofmagnetic (e.g., the I/O transceiver may include a giantmagnetoresisitive or tunnel-magnetoresistance reader) and optical (e.g.,the I/O transceiver may include one or more additional opticalchannels).

Regardless of the pattern, in one or more embodiments, the first set ofoptical pathways 110 may intersect with the second set of opticalpathways 112 to define a grid as will be described with respect to FIGS.2-3. The intersections may be used to connect various optical pathways102 to define a plurality of waveguides as will be described furtherherein with respect to FIGS. 2-3 and 8A-8B. Thus, the plurality ofoptical pathways 102 may be described as being used to define or form aplurality of optical waveguides. Each of the plurality of opticalwaveguides may extend from an optical input configured to receiveoptical data signals from the optical transmitting portions of the I/Oapparatus 50 to an optical output configured to transmit optical datasignals to the optical receiving portions of the I/O apparatus 50 aswill be described further herein. Further, the waveguides may define aplurality of optical switching regions. Each of the plurality of opticalswitching regions may include a set, or portion, of the plurality ofwaveguides that will be aligned with one or both of the transmitting andreceiving portions of the I/O apparatus 50 at the same time as will befurther described herein.

The optical switching medium 100 may be movable at least with respect tothe I/O apparatus 50, and in particular, with respect to thetransmitting and receiving portions positioned, or located on, the headportion 56. In this embodiment, the optical switching medium 100 may berotatable about the central axis 103 similar to, for example, a harddisc drive. Additionally, the movement of the optical switching medium100 may be described relative to the housing 12 in that, for example,the optical switching medium 100 may be movable relative to the housing12. To provide such movement, the device 10 may further include anoptical switching medium actuator operably coupled to the opticalswitching medium 100 to move the optical switching medium 100 in arotational manner about the central axis 103.

Further, as previously described, the I/O apparatus 50 may also bemovable relative to the optical switching medium 100 and the housing 12.In some embodiments, only one of the I/O apparatus 50 and the opticalswitching medium 100 may be movable relative to a fixed reference point.For example, the I/O apparatus 50 may not be movable relative to thehousing 12 while the optical switching medium 100 is movable relative tothe housing 12. Further, for example, the I/O apparatus 50 may bemovable relative to the housing 12 while the optical switching medium100 may not be movable relative to the housing 12.

The movement of the optical switching medium 100 may generally be at aconstant rate such as, e.g., 5400 rotations per minute (RPM) or 7200RPM. A constant rate may provide accurate predictable positioning of theI/O apparatus 50 with respect to the optical switching medium 100 suchthat one or more devices connected thereto may “know” when particularoptical switching regions are able to be utilized. In this way, one ormore devices may “know” when to send optical data signals to the device10 so as to be switched, or routed, according the device 10 intention.In one embodiment, the device 10 may communicate with the operablyconnected devices such that such devices have synchronization knowledgeof the switching possibilities provided by the device 10.

The optical switching medium 100 may also move in other ways thanrotation. For example, the optical switching medium 100 may move withina plane along a first axis 11 that is parallel (e.g., extends along) theplane as shown in FIG. 1B. As shown, the substrate 104 of the opticalswitching medium 100 may linearly move, or oscillate, right and leftalong the axis 11 while the I/O apparatus 50 moves up or down (relativeto the page) along axis 13. In this way, the I/O apparatus 50 may bepositionable about any portion or region of the optical switching medium100 similar as the device of FIG. 1A. In this embodiment, the substrate104 is rectangular. In other embodiments, the substrate 104 may be anysize or shape to facilitate the optical switching functionalitydescribed herein. Additionally, the optical switching medium 100 mayoscillate (e.g., move back-and-forth) at a frequency along a single axis(where, e.g., the single axis 13 extends along the longitudinal axis ofthe optical switching medium 100). Further, although this embodimentdepicted in FIG. 1B moves linearly along a single axis, it is to beunderstood that the substrate 104 may along more than single axis whilelying a single plane. In one embodiment, the substrate 104 may movealong each of the first axis 11 and the second axis 13 while the I/Oapparatus 50 is movable or stationary.

In another embodiment, the I/O apparatus 50 may be sized so as to coverat least one dimension of the optical switching medium 100 such that theI/O apparatus 50 may not need to move. In other words, the I/O apparatus50 may remain stationary as the optical switching medium 100 moves withrespect to the I/O apparatus 50 to provide access to all of the opticalwaveguides and optical switching regions as further described herein.

Further, the optical switching medium 100 may move along more than oneaxis. For example, the optical switching medium 100 may moveback-and-forth along a first axis and back-and-forth along a secondaxis. Both the first axis and the second axis may lie in the same planeor may not lie in the same plane. Further, the first axis may beperpendicular to the second axis in some embodiments.

A plan view and an image of an illustrative intersection 109 betweenoptical pathways 102 of the optical switching medium 100 are depicted inFIGS. 2-3. As shown, a first optical pathway 110 intersects with asecond optical pathway 112, each pathway 110, 112 share a similargeometric profile as described herein. The intersection 109 may bedesigned to allow optical data signals to pass through the intersection109 along the first optical pathway 110 with interfering with opticaldata signals passing through the intersection 109 along the secondoptical pathway 112. In other words, data optical signals travelingalong the first optical pathway 110 may continue traveling along thefirst optical pathway 110 without changing direction due to interferenceby the second optical pathway 112.

Additionally, the intersection 109 may be configured to redirect, ormove, optical data signals from the first optical pathway 110 to thesecond optical pathway 112 or from the second optical pathway 112 to thefirst optical pathway 110 when desired to provide the optical waveguidesof the optical switching medium 100 as described in more detail furtherherein. In one embodiment, an evanescent coupler 115 may be used toredirect, or move, optical data signals from the first optical pathway110 to the second optical pathway 112 or from the second optical pathway112 to the first optical pathway 110. For example, optical data signalsmay be transmitted in the first optical pathway 110 represented by arrow90. Such optical data signals 90 may be evanescently coupled to a firstsegment 116 the evanescent coupler 115 and transmitted around the curve,or bend, of the evanescent coupler 115 to the second segment 117 of theevanescent coupler 115. The second segment 117 of the evanescent coupler115 may be evanescently coupled to the second optical pathway 112 totransmit in the optical data signals along the second optical pathway112 as indicated by arrow 92. Thus, data optical signals transmitted onthe first optical pathway 110 may be transmitted onto the second opticalpathway 112 via the evanescent coupler 115. Similar to the opticalpathways 102, 110, 112, the evanescent coupler 115 may include one ormore polymers such as, e.g., polyacrylate, polysiloxane, polynorbonene,silicon nitride, etc. and/or one or more glasses such as, e.g.,chalcogenide glasses, toughed alkali-aluminosilicate sheet glass, etc.Further, to provide the evanescent coupling between the evanescentcoupler 115 and the respective optical pathways 110, 112, the evanescentcoupler 115 may be spaced apart, or gapped, from the respective opticalpathways 110, 112 an evanescent coupling distance so as to provide theevanescent coupling therebetween.

It is to be understood that this evanescent coupling distance may changedepending on a plurality of factor such as, e.g., materials, geometry,position, etc. of the evanescent coupler 115 and the optical pathways110, 112. For example, the crossover length of an evanescent couplingmay be described as the length where all the power of the optical datasignals is transferred between waveguides. The crossover length may bedescribed as a function of the spacing, or gap, between the evanescentlycoupled portions, wherein the crossover length increases in response tothe spacing, or gap, increasing. For example, if the spacing, or gap,between the evanescently coupled portions, such as the first opticalpathway 110 and the first segment 116 of the evanescent coupler, is 200nanometers, then the cross-over length may be about 1 micrometer.Evanescent coupling spacing may be in the 100s of nanometer gap betweenthe two portions to be coupled.

An image of an illustrative intersection 109 between optical pathways102 of the optical switching medium 100 depicted in FIG. 3 illustratesthat an illustrative intersection may provide insertional loss at 1310nanometers of 0.0168 decibels (dB) and crosstalk of −37 dB, andwavelength sensitivity of 0.09 dB in the 60 nanometer range.

An illustrative I/O apparatus 50 is depicted in FIGS. 4-6. The I/Oapparatus 50 is depicted transparently in FIG. 4 so that internalcomponents and such internal components positioning and routing may beshown. The I/O apparatus 50 as depicted includes a plurality of opticaltransmitting portions 60 and a plurality of optical receiving portions62. Although in this embodiment the I/O apparatus 50 includes two rowsof six optical transmitting portions 60 and two rows of six opticalreceiving portions 62, it is to be understood that any number of opticalreceiving and transmitting portions 60 may be utilized in anyarrangement.

As described herein, each of the optical transmitting portions 60 may beconfigured to receive optical data signals from the I/O ports 14 of thedevice 10 via on one or more or a plurality of optical channels 53 asshown in FIG. 1A and transmit such optical data signals to the opticalswitching medium 100. Further, each of the optical receiving portions 62may be configured to receive optical data signals from the opticalswitching medium 100 and to transmit such received optical data signalsto the I/O ports 14 of the device 10 via on one or more or a pluralityof optical channels 53.

As shown in FIGS. 4-5, each of the optical transmitting and receivingportions 60, 62 may include multiple segments or regions. In oneembodiment, it may be described that each of the optical transmittingand receiving portions 60, 62 includes an evanescent coupling segment 61terminating an end region of the each optical transmitting and receivingportions 60, 62. The evanescent coupling segments 61 may extend in adirection parallel to that what they are to be evanescently coupled tofor a crossover, or interaction, length so as to provide evanescentcoupling therebetween as will be shown and described with respect toFIGS. 5-6. In other words, at least a portion, namely, e.g., theevanescent coupling segments 61, of the optical transmitting portions 60and receiving portions 62 of the I/O apparatus 50 may extend parallel toat least a portion (e.g., the optical inputs and outputs as furtherdescribed herein) of the plurality of optical pathways 102 of theoptical switching medium 100.

Although the illustrative embodiment depicted in FIGS. 4-6 utilizeevanescent coupling between optical transmitting and receiving portions60, 62 and the waveguides of the optical switching medium 100, it to beunderstood that optical data signals may be transmitted therebetweenusing any techniques, structures, and processes configured to do so. Forexample, in one embodiment, the optical transmitting and receivingportions 60, 62 and the waveguides of the optical switching medium 100may be configured to provide radiative coupling therebetween using,e.g., appropriate lens, mirrors, gratings, inverse couplers, etc.

Further, each optical transmitting and receiving portions 60, 62includes an optical coupler 63, an optical connecting element 65, andthe evanescent coupling segment 61 (labeled on a single opticaltransmitting portion 60 in FIG. 5 and on a single optical receivingportion 62 in FIG. 6). The optical coupler 63 may a portion, or region,of the optical transmitting and receiving portions 60, 62 that isconfigured to be operatively coupled to the optical channels 53 of theI/O apparatus 50 to operatively couple the optical transmitting andreceiving portions 60, 62 to the I/O ports 14. The optical coupler 63 isalso operatively coupled to the optical connecting element 65. Theoptical connecting element 65 may be configured to transmit optical datasignals between (e.g. from or to) the optical coupler 63 and theevanescent coupling segment 61. More specifically, for the opticaltransmitting portions 60, the optical connecting element 65 may beconfigured to transmit optical data signals from the optical coupler 63to the evanescent coupling segment 61 for transmission of the opticaldata signals to the waveguides of the optical switching medium 100. Forthe optical receiving portions 62, the optical connecting element 65 maybe configured to transmit optical data signals from the evanescentcoupling segment 61 to the optical coupler 63 for transmission of theoptical data signals to the optical channels 53.

The evanescent coupling segments 61 may extend parallel to the opticalpathways 102 of the optical switching medium 100 so as to provide anappropriate crossover length for evanescent coupling therebetween.Additionally, as shown, each of the evanescent coupling segments 61 maydefine a pair of stepped regions on either end of the evanescentcoupling segment 61 to provide low-loss routing of light as will befurther described with reference to FIG. 7.

As shown, the optical switching medium 100 may include, or be definedby, the substrate 104. The substrate 104 may include one or more or aplurality of layers so as to provide the functionality of the opticalswitching medium 100 described herein. In the example depicted in FIGS.4-5, the substrate 104 includes a base layer 106. The base layer 106 mayinclude (e.g., be formed of) one or more materials such as, e.g.,silicon, silicon dioxide, silicon nitride, AlTiC, alumina etc. Theplurality of optical pathways 102 may be positioned within the baselayer 106. In one embodiment, the optical pathways 102 may be formed, ordefined, within the base layer 106 using semiconductor processingtechniques (e.g., etching, deposition, etc.). It is to be understoodthat the optical pathways 102 may be formed using any techniques orprocesses. Further, as shown, the optical pathways 102 may extend longerin the concentric or arcuate direction as depicted in the cross-sectionof FIG. 6 than the radial direction as depicted in the cross-section ofFIG. 5 so as to provide an appropriate crossover length for effectiveevanescent coupling to the evanescent coupling segments 61.

A cover layer 107 may be provided over the base layer 106 and theoptical pathways 102. The cover layer 107 may include (e.g., be formedof) one or more materials such as, e.g., diamond-like carbon, etc.

A more detailed cross-sectional diagram of an illustrative I/O apparatus50 and optical switching medium 100 is depicted in FIG. 7. In thisdepiction, the evanescent coupling segment 61 is depicted spaced awayfrom an optical pathway 102 by a gap distance 70. The gap distance 70may be between about 100 nm to about 300 nm. In one embodiment, the gapdistance 70 is about 250 nm. The evanescent coupling segment 61 maydefine a thickness 71 of about 150 nm to about 250 nm. In oneembodiment, the evanescent coupling segment 61 may have, or define, athickness of 220 nm. Further, the evanescent coupling segment 61 maydefine one or more step regions 72 (e.g., curves, bends, etc. away fromthe optical switching medium 100) defining a radius of about 5micrometers to about 15 micrometers. In one embodiment, the step regions72 define a radius of about 5 micrometers.

The head portion 56 may include one or more or a plurality of layers soas to provide the functionality of the I/O apparatus 50 describedherein. In the example depicted in FIG. 7, the head portion 56 mayinclude a base substrate 57 and a cover layer 58. The base substrate 57may include (e.g., be formed of) one or more materials such as, e.g.,aluminum oxide, silicon dioxide, etc. The cover layer 58 may include(e.g., be formed of) one or more materials such as, e.g., diamond-likecarbon, etc. The cover layer 58 may define a thickness 73 of about 1 nmto about 5 nm. In one embodiment, the cover layer 58 has, or defines athickness 73 of 2 nm.

Further, the base substrate 57, the cover layer 58, and the evanescentcoupling segment 61 may be spaced apart from each in using variousdistances so as to provide the functionality described herein. Forexample, the cover layer 58 may be spaced apart from the evanescentcoupling segment by a distance 74 that is about 5 nm to about 20 nm. Inone embodiment, the distance 74 is 5 nm.

Similar to the optical switching medium 100 described herein withreference to FIGS. 5-6, the optical switching medium 100 may include thebase layer 106 and the cover layer 107. The cover layer 107 may define athickness 75 of about 1 nm to about 3 nm. In one embodiment, the coverlayer 107 defines, or has, a thickness 75 of 1.5 nm. The opticalpathways 102 may define a thickness 76 of about 1 to about 5 nm. In oneembodiment, the optical pathways 102 define, or have, a thickness 76 of3 nm.

Further, the base layer 106 and the cover layer 107, and the opticalpathways 102 may be spaced apart from each in using various distances soas to provide the functionality described herein. For example, the coverlayer 107 may be spaced apart from the optical pathways by a distance 77that is about 1 nm to about 20 nm. In one embodiment, the distance 77 is10 nm.

Additionally, although the optical pathways 102 in this example aredepicted as existing in a single layer, it is to be understood that theoptical pathways 102 can extend in more than one (e.g., a plurality) ofdifferent layers so as to define the optical switching regions 140 asdescribed herein. For instance, one or more optical structures such aslight escalators, evanescent couplers, gratings, etc. may be used tomove optical signals between optical pathways 102 located in differentlayers. In other words, the optical pathways 102 may be occupy differentlevels, or layers, in the medium 100. The light can be transferred froma shallower layer to a deeper layer through the use of variousstructures or mechanisms.

Still further, the head portion 56 of the I/O apparatus may bepositioned adjacent to or spaced apart from to the optical switchingmedium 100 so as to provide the functionality provided herein. In one ormore embodiments, the head portion 56, or in particular, the cover layer58 of the head portion 56 may be in contact with, or adjacent to, theoptical switching medium 100, or in particular, the cover layer 107 ofthe optical switching medium 100. In one or more embodiments, the headportion 56, or in particular, the cover layer 58 of the head portion 56may be spaced apart from the optical switching medium 100, or inparticular, the cover layer 107 of the optical switching medium 100, bya gap, or fly height, 78. Thus, gap, or fly height, 78 may be extendbetween the head portion 56 and the optical switching medium 100. Thegap, or fly height, 78 may be between about 150 nm to about 250 nm. Inone embodiment, the gap 78 is 200 nm.

As described herein, the optical switching medium 100 includes aplurality of optical waveguides 120 that are defined by the plurality ofoptical pathways 102. Four illustrative optical waveguides 120 a, 120 b,120 c, 120 d are depicted in FIG. 8A, and four illustrative opticalwaveguides 120 e, 120 f, 120 g, 120 h are depicted in FIG. 8B. Each ofthe optical waveguides 120 may be described as an optical path extendingfrom an optical input 121 to an optical output 122. Each optical input121 may be configured to receive (e.g., via evanescent coupling) opticaldata signals from one of the optical transmitting portions 60 and eachoptical output 122 may be configured to transmit (e.g. via evanescentcoupling) optical data signals to one of the optical receiving portions62 when such optical inputs and outputs 121, 122 are aligned with thetransmitting and receiving portions 60, 62 of the I/O apparatus 50.Thus, with reference to FIG. 8A, the I/O apparatus 50 may transmit fouroptical data signals into the optical waveguides 120 a, 120 b, 120 c,120 d via the respective optical inputs 121 and then receive the fouroptical data signals from the optical waveguides 120 a, 120 b, 120 c,120 d via the respective optical outputs 122.

Groups of optical waveguides configured to be aligned with the I/Oapparatus 50 at the same time may be referred to as optical switchingregions 140. For example, the four illustrative optical waveguides 120a, 120 b, 120 c, 120 d may collectively be referred to as an opticalswitching region 140 a, and the four illustrative optical waveguides 120e, 120 f, 120 g, 120 h may collectively be referred to as an opticalswitching region 140 b. The optical switching medium 100 may include aplurality of optical switching regions 140, each defined by a pluralityof optical waveguides 120. Further, each of the plurality of opticalswitching regions 140 may provide different switching functionality thanat least one other optical switching region 140. For example, oneoptical switching region 140 may receive optical data signals at theoptical inputs 121 and switch the optical data signals to differentoptical outputs 122 than at least one other optical switching region 140of the illustrative optical switching medium 100. In one embodiment,each of the optical switching regions 140 of the optical switchingmedium 100 provides different switching functionality than every otheroptical switching region 140.

Two examples of this different switching functionality will be describedherein with reference to the optical switching regions 140 a, 140 b ofFIGS. 8A-8B. As shown in FIG. 8A, for example, optical data signal I maybe received by the optical input 121 of the optical waveguide 120 a inrow A, optical data signal II may be received by the optical input 121of the optical waveguide 120 b in row B, optical data signal III may bereceived by the optical input 121 of the optical waveguide 120 c in rowC, and optical data signal IV may be received by the optical input 121of the optical waveguide 120 d in row D. The optical data signal I maypropagate along the optical waveguide 120 a to the optical output 122 inrow G, the optical data signal II may propagate along the opticalwaveguide 120 b to the optical output 122 in row E, the optical datasignal III may propagate along the optical waveguide 120 c to theoptical output 122 in row F, and the optical data signal IV maypropagate along the optical waveguide 120 d to the optical output 122 inrow H. In this way, when an I/O apparatus 50 is positioned to transmitand receive data optical signals from the optical switching region 140of FIG. 8A, the I/O apparatus 50 may transmit optical data signal I onrow A, optical data signal II on row B, optical data signal III on rowC, and optical data signal IV on row D using the transmitting portions60 and receive optical data signal I on row G, optical data signal II onrow E, optical data signal III on row F, and optical data signal IV onrow H using the receiving portions 62.

As shown in FIG. 8B, for example, optical data signal V may be receivedby the optical input 121 of the optical waveguide 120 e in row A,optical data signal VI may be received by the optical input 121 of theoptical waveguide 120 f in row B, optical data signal VII may bereceived by the optical input 121 of the optical waveguide 120 g in rowC, and optical data signal VIII may be received by the optical input 121of the optical waveguide 120 h in row D. The optical data signal V maypropagate along the optical waveguide 120 e to the optical output 122 inrow G, the optical data signal VI may propagate along the opticalwaveguide 120 f to the optical output 122 in row F, the optical datasignal VII may propagate along the optical waveguide 120 g to theoptical output 122 in row E, and the optical data signal VIII maypropagate along the optical waveguide 120 h to the optical output 122 inrow H. In this way, when an I/O apparatus 50 is positioned to transmitand receive data optical signals from the optical switching region 140 bof FIG. 8B, the I/O apparatus 50 may transmit optical data signal V onrow A, optical data signal VI on row B, optical data signal VII on rowC, and optical data signal VIII on row D using the transmitting portions60 and receive optical data signal V on row G, optical data signal VI onrow F, optical data signal VII on row E, and optical data signal VIII onrow H using the receiving portions 62.

The optical switching medium 100 may include a plurality of opticalswitching regions 140 patterned, or arranged, thereabout as depicted inFIG. 9. The optical switching medium 100 may move with respect to theI/O apparatus 50 so as to align the optical transmitting portions andoptical receiving portions with one optical switching region 140 at atime such that the I/O apparatus 50 can transmit and receive opticaldata signals switched according to the optical switching region 140.

In the example depicted in FIG. 9, each of plurality of opticalswitching regions 140 includes four optical waveguides including opticalinputs and optical outputs arranged parallel to the direction of motion190 of the optical switching medium 100. The optical switching regions140 of FIG. 9 are similar to the layout of the optical switching regions140 of FIGS. 8A-8B. In fact, the optical switching region 140 a and theoptical switching region 140 b are both identified in FIG. 9.

The direction of travel 190 of the optical switching medium 100 isdepicted to indicate how the optical switching regions 140 will movewith respect to the I/O apparatus 50. The optical inputs 121 and theoptical outputs 122 may be described as extending along the direction oftravel 190. More specifically, the optical inputs 121 and the opticaloutputs 122 of each single optical switching region 140 may aligned witheach other in a direction parallel to the direction of travel 190.Additionally, the optical transmitting portions 60 and the opticalreceiving portions 62 of the I/O apparatus 50 may be aligned in asimilar fashion such that the optical transmitting portions 60 and theoptical receiving portions 62 may be aligned with a single opticalswitch region 140 at a time to transmit optical data signals thereto andreceive optical data signals therefrom.

Nonetheless, it is to be understood that the optical switching regions140, and respective optical waveguides thereof, depicted in FIG. 9 aremerely one example, and the optical switching regions 140, andrespective optical waveguides thereof, may be positioned or arrangedabout the optical switching medium 100 in any configuration so as toprovide the functionality described herein.

Furthermore, in one or more embodiments, the number of gimbal assemblies54, the number of head portions 56 per gimbal assembly 54, the number ofI/O apparatus 50 per surface of optical switching medium 100, and thenumber of optical switch media 100 surfaces per device are intentionallyunspecified. Additionally, the use of multiple head portions 56 peroptical switching medium 100 surface such as, for example, a headportion 56 dedicated to input and a head portion 56 dedicated to output,or head portions 56 servicing wholly independent input/outputs from oneanother, are within the scope of this disclosed solution.

Still further, input to output optical waveguide, or pathway, design canbe in radial, circumferential, and z-directions (deposition direction)of the optical switching medium 100. Also, “disc” sectors areas may notbe of uniform angular dimension. If longer a particular permutation ofinput-to-output coupling is utilized, then that pathway can be situatedwithin a sector having a longer angular fraction of the disc.

Since the I/O apparatus 50 is capable of rotation, different radiallocations of the optical switching medium 100 can be accessed. Designingdifferent input/output coupling patterns at each radius provides anotherenabler for different dwell times in a single pathway combination, whichmay be achieved by consuming different angular fractions per sector ateach of the different radii. Different radii can also be accessed whencertain pathways, e.g., input X to output Y, may be required for longerperiods of time. For example, a particular radial section of the mediacan be dedicated to this pathway (which does not need to be limited to asingle input/output pairing) and can be accessed by rotating I/Oapparatus 50 to the desired radial track.

All patents, patent documents, and references cited herein areincorporated in their entirety as if each were incorporated separately.This disclosure has been provided with reference to illustrativeembodiments and is not meant to be construed in a limiting sense. Asdescribed previously, one skilled in the art will recognize that othervarious illustrative applications may use the techniques as describedherein to take advantage of the beneficial characteristics of theapparatus and methods described herein. Various modifications of theillustrative embodiments, as well as additional embodiments of thedisclosure, will be apparent upon reference to this description.

What is claimed:
 1. Apparatus comprising: an optical switching mediumcomprising a plurality of optical waveguides defining a plurality ofoptical switching regions, each of the plurality of waveguides extendingfrom an optical input to an optical output, each optical switchingregion routing at least one optical input to a different optical outputthan at least one other optical switching region; and an opticalswitching medium actuator operably coupled to the optical switchingmedium to move the optical switching medium to receive optical signalswith the optical inputs of the optical waveguides of the opticalswitching regions and to transmit optical signals with the opticaloutput of the optical waveguides of the optical switching regions toprovide switching of the received optical signals.
 2. The apparatus ofclaim 1, wherein the optical switching medium actuator moves the opticalswitching medium rotatably about a rotation axis.
 3. The apparatus ofclaim 1, wherein the optical switching medium actuator moves the opticalswitching medium along at least one axis.
 4. The apparatus of claim 1,wherein each optical switching region routes at least one optical inputto a different optical output than at least one other optical switchingregion.
 5. The apparatus of claim 1, wherein the optical switchingmedium comprises: a plurality of first optical pathways; and a pluralityof second optical pathways, each second optical pathway opticallycouples two of the first optical pathways, wherein the plurality ofwaveguides are defined using the first and second optical pathways. 6.The apparatus of claim 5, wherein the first optical pathways extendarcuately and the second optical pathways extend radially.
 7. Theapparatus of claim 5, wherein each second optical pathway opticallycouples two of the first optical pathways via an evanescent coupler. 8.A method comprising: moving an optical switching medium comprising aplurality of optical waveguides defining a plurality of opticalswitching regions; transmitting a plurality of optical signals to theplurality of optical switching regions to switch one or more of theplurality of optical signals; and receiving one or more switched opticalsignals from the plurality of optical switching regions.
 9. The methodof claim 8, wherein transmitting a plurality of optical signals to theplurality of optical switching regions to switch one or more of theplurality of optical signals comprises aligning an input/output (I/O)apparatus comprising a plurality of optical transmitting portions withthe plurality of optical switching regions.
 10. The method of claim 9,wherein transmitting a plurality of optical signals to the plurality ofoptical switching regions to switch one or more of the plurality ofoptical signals comprises evanescently coupling the plurality of opticaltransmitting portions with the plurality of optical switching regions.11. The method of claim 8, wherein aligning an I/O apparatus comprisesmoving the I/O apparatus.
 12. The method of claim 8, wherein receivingone or more switched optical signals from the plurality of opticalswitching regions comprises aligning an input/output (I/O) apparatuscomprising a plurality of optical receiving portions with the pluralityof optical switching regions.
 13. The method of claim 8, wherein movingthe optical switching medium comprising rotating the optical switchingmedium about an axis.
 14. The method of claim 8, wherein moving theoptical switching medium comprising linearly oscillating the opticalswitching medium along an axis.
 15. A system comprising: an input/output(I/O) apparatus comprising: a plurality of optical transmittingportions, and a plurality of optical receiving portions; and an opticalswitching medium comprising a plurality of optical waveguides defining aplurality of optical switching regions, the optical switching mediummovable with respect to the I/O apparatus to provide switching ofoptical signals between the plurality of optical transmitting portionsand the plurality of optical receiving portions by aligning the opticaltransmitting portions and optical receiving portions of the I/Oapparatus with the plurality of optical switching regions to receiveoptical signals from the optical transmitting portions and to transmitoptical signals to the optical receiving portions.
 16. The system ofclaim 15, wherein the optical transmitting portions and receivingportions are evanescently couplable to the optical waveguides of theplurality of optical switching regions to transmit thereto and receiveoptical signals therefrom when aligned thereto.
 17. The system of claim15, wherein at least a portion of the optical transmitting portions andreceiving portions of the I/O apparatus extend parallel to at least aportion of the plurality of optical waveguides of the optical switchingmedium.
 18. The system of claim 15, further comprising a gimbal assemblycoupled to the I/O apparatus to suspend the I/O apparatus away from theoptical switching medium.
 19. The system of claim 15, wherein the devicefurther comprises an optical switching medium actuator to move theoptical switching medium rotatably about a rotation axis.
 20. The systemof claim 15, wherein the device further comprises an optical switchingmedium actuator to move the optical switching medium along at least oneaxis.
 21. The system of claim 15, wherein the device further comprisesan I/O actuator to move the I/O apparatus relative to the opticalswitching medium.
 22. The system of claim 15, wherein each of theplurality of waveguides extends from an optical input to an opticaloutput, wherein the optical inputs and optical outputs of only oneoptical switching region are aligned with the transmitting portions andreceiving portions of the I/O apparatus at a time, wherein each opticalswitching region routes at least one optical input to a differentoptical output than at least one other optical switching region.
 23. Thesystem of claim 15, wherein the plurality of optical waveguidescomprises: a plurality of first optical pathways; and a plurality ofsecond optical pathways, each second optical pathway optically couplestwo of the first optical pathways, wherein the plurality of waveguidesare defined using the first and second optical pathways.
 24. The systemof claim 23, wherein the first optical pathways extend arcuately and thesecond optical pathways extend radially.
 25. The system of claim 23,wherein each second optical pathway optically couples two of the firstoptical pathways via an evanescent coupler.
 26. A system comprising: aplurality of optical switching devices, each of the plurality of opticalswitching devices corresponding to and operable to switch opticalsignals to and from a node to other optical switching devices of theplurality of optical switching devices, each optical switching devicecomprising an optical switching medium movable to switch optical signalsto and from the node, the optical switching medium comprising aplurality of optical waveguides defining a plurality of opticalswitching regions.
 27. The system of claim 26, wherein each of theplurality of waveguides extends from an optical input to an opticaloutput, wherein the optical inputs and optical outputs of only oneoptical switching region are aligned with transmitting portions andreceiving portions of I/O apparatus at a time, wherein each opticalswitching region routes at least one optical input to a differentoptical output than at least one other optical switching region.